The present invention relates generally to caster assemblies. More particularly, in various embodiments, the present invention relates to caster assemblies for use with ride-on devices. Even more specifically, this invention, in particular embodiments, pertains to an adjustable rocking action caster assembly for improved performance of recreational skateboards, caster boards, and the like.
There are numerous ride-on devices in the marketplace. Ride-on devices take many forms and may be used for exercise, entertainment or both. They may have a non-descript, mostly functional aesthetic form, like a skateboard or scooter, or they may be made to look like a vehicle, an animal or, a fictional character as with many preschool toys.
Conventional skateboards are generally supported by two-wheeled truck assemblies attached to the undersides of the boards. Such skateboards have long been popular, but are limited in the sense that the rider could realistically accelerate on a level or uphill surface only by removing one of his or her feet from the board and pushing off the ground. Typically such skateboards were also limited in the degree of steering that was possible, as where the turning radius reached a certain angle, the wheels would touch the board.
There is a desire and need in the marketplace for ride-on products that can be propelled in a way that is more novel than simply pushing off, and that may provide sharper turns if desired.
Caster boards were subsequently developed to address the limitations of skate boards. U.S. Pat. No. 7,195,259 provides certain examples of caster, boards. Caster boards typically have comprised one or two boards, with at least one swivel caster wheel assembly in front and at least one in the rear of the caster board. The rider twists his or her body to the left and to the right to accelerate the caster board or to turn it within a relatively small turning radius. This is accomplished by having the wheels rotate around the wheel axis when the board is twisted in either direction, where the wheel axis is mounted at an acute angle with respect to the bottom, front and back of the caster board.
In these prior art caster boards, the distance from the bottom side of the board to the contact point of the wheel to the riding surface increases as the wheel bracket rotates around the axis in either direction from its lowest forward facing position until the distance reaches maximum when the wheel bracket is rotated 180 degrees from its neutral position. Propulsion is a resultant force causing the wheels to move along the riding surface according to their bias as a rider applies a force to twist the board and cause the casters to rotate around the axis. In common caster boards this action will produce propulsion in the general direction opposite of the acute angle formed by the wheel axis to the board. These prior art caster boards have a defined front and a defined back. The front and back are defined by the acute angle of the wheel axis. When the wheel bracket is rotated 180 degrees around the axis, the distance between the bottom side of the board and the point where the wheel contacts the riding surface is at its maximum. Because there is no force to bias the wheels against, propulsion in this direction is not possible. Therefore, the prior art caster board has a defined front and back and are unidirectional with regard to propulsion.
In contrast, skateboards and the art of skateboarding have benefitted in regard to the tricks able to be performed and their subsequent popularity by their ability to go either direction with equal capability. Therefore it would be beneficial to the art if a caster board could be bidirectional and travel in either direction with equal capability.
Moreover, in common prior art caster boards, the angle of the wheel axis cannot be adjusted by the rider according to his skill level, chosen activity or preference. In contrast, many sport type ride-on devices, such as BMX bicycles and common skateboards, retain the interest of the user partly due to the fact they can be customized to affect performance via changeable parts such as sprockets, trucks and other paraphernalia.
Typical prior art caster boards have a front and a back defined by its ability to propel itself in a general direction which is determined by the acute angle at which the wheel axis is mounted. This design limits caster boards to be unidirectional and leaves a desire in the marketplace unfulfilled.
Some ride-on devices have used a spring to work against the rotation of the wheel assembly along the wheel axis, thus creating a force that replaces the gravitational force used in other prior art devices. This method still provides forward motion resulting from side-to-side, or twisting, forces applied by the rider. However, this does not allow full rotation of the wheel assembly which limits the maneuverability of the ride-on device. Moreover, the spring has a set tension so performance varies greatly with the weight of the rider.
It is desirable therefore to provide a caster assembly that permits full rotation of the wheel for bi-directional propulsion. This improved performance may include sharper turns, bi-directional travel, and user-adjustable components for various preferences and/or skill levels as examples. Other needs and potential for benefit may be apparent to persons of skill in the art having studied this document.